Cold Blood by T. Strange

Ghost wards are failing. Mediums are vanishing. Someone—or something—is stirring up the ghosts of Toronto. It’s up to psychic medium Harlan Brand to find out why.

After defeating a serial killer who could control ghosts, psychic medium Harlan Brand is feeling much more confident in his abilities working for the Toronto Police Service with his partner, Hamilton, as they protect the city from dangerous spirits.
He is expanding his social circle, however reluctantly, to include the other police mediums and Morgan Vermeer, another graduate from the Centre—a school for training psychic children.
Harlan and his boyfriend, Charles Moore, are continuing to explore BDSM, their relationship and Charles’ strange ability to shield people from ghosts.
Hoping to find answers about Charles’ power and the serial killer, Harlan returns to the Centre only to find that one of its ghost wards—magical symbols that spirits can’t cross—is broken, and it’s a mystery as to how and why.
The calm and order that Harlan has been building up in his life are shattered when wards start failing across the city and mediums begin to disappear, including one of his new friends and a student from the Centre.
Someone—or something—is stirring up the ghosts of Toronto.